Dear reader,This thesis is the last step towards completing my Master of Science in Mechanical Engineering at the University of Technology in Delft. It has been quite the journey, which started with the track Multi-Machine Engineering. During the second year of my masters, I did a literature study under the supervision of Vasso Reppa and Nikos Kougiatsos, where I reviewed the state-of-the-art of the propulsion control in marine vessels. I found that, although there is a great variety in propulsion control systems, no literature considered modular use of the equipment in the power plant. To this end, in collaboration with Vasso, Nikos, and Royal IHC, the main idea for this thesis was proposed.Soon after the initial proposal the main course of the thesis was set, and after the approval of Rudy Negenborn, the journey began. In this work, you may find information about different missions of ships, how these missions dictate the required power, and also how this affects the power plants and the control systems found in various marine vessels. It is shown how this leads to a mission-oriented design of the control system, where equipment can be added, replaced, or removed. Although I did not specialize in control engineering, my skills with MATLAB, developed during the master, greatly helped to resolve most problems, and I am proud to present you my work.I want to start by thanking Vasso and Nikos for their daily supervision and assistance. Nikos is a PhD researcher, and his field of work is very closely related to the topic of this thesis, so he was always able to provide insightful comments and detailed explanations when I found some obstacles. Vasso's input was aimed more towards the presentation and design of the control systems, and was also very helpful with maintaining the right course, and keeping track of the main goal of the thesis. Also, I want to thank Rudy, who was able to provide good feedback during meetings, as he knows a great deal about this topic, and a lot of his work is used in this thesis.Finally, I want to thank my parents, friends and my girlfriend for their support, motivation, and guidance, not only during this thesis, but also during my entire studies at the TU Delft. This journey would not have been the same without you. I wish you a pleasant reading,

Nowadays, marine vessels constitute safety-critical assets facilitating the transport of millions of passengers and tons of cargo worldwide. As such, they require a large number of heterogeneous sensors dispersed in the various on-board machinery for operational and condition monitoring of their vital systems, such as the propulsion system. Despite the vast availability of data from on-board sensors, there is hardly any collaboration between the spatially distributed sensor devices to boost vessel performance. Up to this day, physical redundancy has been mostly discussed in maritime literature and has also been required by certain ship system design regulations. The use of virtual sensors (software-based) has not been properly investigated yet for maritime applications, despite their successful application in other fields like aircraft control and process control. This paper proposes a novel switching mechanism to alternate between physical and virtual sensors used in the primary propulsion control layer of marine vessels aiming to compensate for the effects of sensor faults. The switching mechanism focuses on ensuring the safe performance of the propulsion grid after the sensor faults occur. The software sensors are constructed using mathematical models describing the nonlinear dynamics of the propulsion system and the input and sensor output data. Simulation results are used to illustrate the switching mechanism's performance in the case of a hybrid propulsion system, where the different subsystems are controlled in a distributed configuration.